The United Nations forecasts that the population of the world will reach 9.8 billion by 2050. Many experts are concerned about the earth’s ability to feed so many people. Land-based agricultural resources increasingly struggle to meet this huge increase in demand and fish farming is growing dramatically to fill the gap.
More Fish in the Sea
The UN Food and Agriculture Organisation reports that the average amount of fish eaten per capita globally has more than doubled from 9.0kg in 1961 to 20.2kg in 2015. Of course, there are well-publicised cases of overfishing, but much of this growth has been from aquaculture which has grown from 25.7% of production in 2000 to 46.8% in 2016. These data include finfish, crustaceans and molluscs.
As with any farming, growing large amounts of food in a small space increases the incidence of infection and disease can spread extremely rapidly through a stock of 90,000 fish confined to a pen. Fish farms work hard on hygiene and diet, and minimising stress, to ensure that fish are kept healthy, minimising losses and producing a high-quality product.
Rapid Diagnosis Fights Against Listed Diseases
A key to keeping the stock healthy is the rapid diagnosis of diseases and parasites. Large farms use continuous monitoring of the water, but there is no substitute for visual inspection of the fish, and early detection of small parasites means that facilities need a microscope.
Traditional compound microscopes are difficult to transport and use in remote environments and usually have no way of sharing images for records or a second expert opinion.
A new generation of portable microscopes can capture and share images and videos of parasites and other fish pathology instantly from a standard mobile phone. The image quality is now close to that of a laboratory microscope, but the digital product fits in a jacket pocket and has a flat wipe-clean surface. This new class of high-
resolution, portable microscope dramatically improves the speed of diagnosis and therefore productivity in aquaculture environments. It is now possible to sample, diagnose, and treat serious health conditions within a few minutes. Site staff can even get a second expert opinion in the time it takes to send and receive an email.
The importance of rapid diagnosis can be understood by looking at Gyrodactylus salaris, or salmon fluke, a microscopic parasite that feeds on the flesh and mucus of salmon and other freshwater fishes. It has caused mortalities of up to 98% in wild Atlantic salmon populations in Norway. Some stocks have been lost completely or destroyed by adding pesticides to infected rivers, killing parasites and fish, though this treatment is no longer common. Gyrodactylus salaris is so serious that it is classified as a listed disease that must be reported to the authorities. Rapid detection is vital in the removal of infected fish and the fight against these contagious diseases.
Pocket Digital Microscopes Ready to Go Anywhere
The step forward in digital microscopes has been enabled by using high-quality, low-cost parts designed for mobile phones to make highly compact, robust instruments. Originally these devices were low-cost, low-resolution, USB-connected devices, with limited application in the aquaculture market. However, more recent microscopes are pocket-sized and use a wireless connection to deliver 1-micron resolution images to a standard mobile phone. The newer products feature a robust stage and transmitted illumination, like a compound microscope. Best of all, high-resolution images and even videos can be shared instantly for a second opinion.